JP2004222542A

JP2004222542A - Method for producing lactic acid fermented food

Info

Publication number: JP2004222542A
Application number: JP2003011563A
Authority: JP
Inventors: Takahiro Kashima; 隆洋加島
Original assignee: Gifu Prefecture
Current assignee: Gifu Prefecture
Priority date: 2003-01-20
Filing date: 2003-01-20
Publication date: 2004-08-12
Anticipated expiration: 2023-01-20
Also published as: JP4132037B2

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for producing a lactic acid fermented food, by which contamination by putrefactive bacteria is readily and effectively prevented and a lactic acid fermented food subjected to lactic acid fermentation excellently in a short period is readily produced. <P>SOLUTION: The first method for producing a lactic acid fermented food comprises adding malted rice to a food material such as fish meat, meat, a vegetable, boiled rice, etc., and inoculating a low-temperature lactic acid bacterium and carrying out fermentation and aging at 0-10°C. The malted rice is obtained by making steamed rice inoculated with a lactic acid bacterium into malted rice by addition of the culture of a nisin-producing lactic acid bacterium or steaming rice immersed in water containing a nutrient component to give steamed rice and inoculating a nisin-producing lactic acid bacterium into the steamed rice to give malted rice. The second method for producing a lactic acid fermented food comprises inoculating a low-temperature lactic acid bacterium into the food material and carrying out preliminary fermentation at 0-10°C before addition of malted rice, then adding malted rice and carrying out fermentation and aging at 0-10°C. The low-temperature lactic acid bacterium is preferably Lactobacillus sake. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

【０００１】
【発明の属する技術分野】
この発明は、かぶらずし、いずし、ねずし等の乳酸発酵食品の製造方法に関するものである。より詳しくは、バチルス属細菌（Ｂａｃｉｌｌｕｓ）や大腸菌群（Ｃｏｌｉｆｏｒｍ）等の有害細菌による汚染を極めて容易かつ効果的に防止しつつ短期間で良好に乳酸発酵した製品を製造することが容易な乳酸発酵食品の製造方法に関するものである。
【０００２】
【従来の技術】
従来より、この種の乳酸発酵食品の製造方法としては、例えば非特許文献１に開示されているように、塩蔵したかぶらとブリを米麹とともにさらに数日間漬け込んで製造され、乳酸発酵は自然発酵に頼られているのが現状である。
【０００３】
【非特許文献１】
久田孝、外２名、“金沢産かぶらずしの細菌フローラ”、日本食品微生物学会誌、（財）東京顕微鏡院、１９９７、１４（２），１１１−１１４
【０００４】
【発明が解決しようとする課題】
ところが、前記非特許文献１では、バチルス属細菌が１０^３〜１０^５個／ｇ、大腸菌群が１０^２〜１０^３個／ｇ検出された製品が報告されている。さらに、同文献では、同じ製造元の製品でも乳酸菌数やｐＨが大きく異なり、品質が安定していないことも報告されている。即ち、この非特許文献１に記載されている自然発酵による製法では、おそらく乳酸菌による発酵が十分に安定していないためにこれらの不具合が発生しているものと考えられる。これらのバチルス属細菌や大腸菌群は、米麹、野菜類、魚肉等の原材料を汚染したものであるが、味や食感を損ねるため、それら原材料及び最終製品に加熱殺菌処理を施すことができない。
【０００５】
バチルス属細菌は、米麹を汚染する代表的な腐敗細菌であるが、耐熱・耐薬品性の高い芽胞を形成するため、かぶらずし等の最終製品中でそれらを死滅させることは困難である。中でもバチルス・セレウス（Ｂａｃｉｌｌｕｓｃｅｒｅｕｓ）は、５℃という低温下でも増殖する食中毒細菌であり注意が必要である。一方、大腸菌群は、汚染指標細菌とされ、それらが検出される食品は食品衛生上好ましくないだけでなく、冷蔵条件下でも食品を腐敗させるものも存在するため注意が必要である。また腸管出血性大腸菌（ＥｎｔｅｒｏｈｅｍｏｒｒｈａｇｉｃＥｓｃｈｅｒｉｃｈｉａｃｏｌｉ）Ｏ１５７は、数１００個程度のごく少量の生菌が経口的に侵入しても感染が成立し、近年ではイクラといった水産加工品が食中毒の原因食品となったことから警戒が必要である。
【０００６】
この発明は、上記のような従来技術に存在する問題点に着目してなされたものである。その目的とするところは、有害細菌による汚染を容易かつ効果的に阻止することができるとともに、短期間で良好に乳酸発酵した乳酸発酵食品を製造することが容易な乳酸発酵食品の製造方法を提供することにある。
【０００７】
【課題を解決するための手段】
上記の目的を達成するために、請求項１に記載の発明の乳酸発酵食品の製造方法は、食品素材に米麹を添加して発酵熟成を行う乳酸発酵食品の製造方法において、前記食品素材に米麹を添加するとともに低温性乳酸菌を接種して０〜１０℃で発酵熟成を行うように構成され、前記米麹は、ナイシン生産性乳酸菌の培養物を添加することにより該乳酸菌が接種された蒸し米を製麹したもの、又は栄養成分を含む水に浸漬させた米を蒸煮した蒸し米にナイシン生産性乳酸菌を接種して製麹したものであることを特徴とするものである。
【０００８】
請求項２に記載の発明の乳酸発酵食品の製造方法は、食品素材に米麹を添加して発酵熟成を行う乳酸発酵食品の製造方法において、前記食品素材に低温性乳酸菌を接種して０〜１０℃で下漬けを行った後、前記米麹を添加して０〜１０℃で発酵熟成を行うように構成され、前記米麹は、ナイシン生産性乳酸菌の培養物を添加することにより該乳酸菌が接種された蒸し米を製麹したもの、又は栄養成分を含む水に浸漬させた米を蒸煮した蒸し米にナイシン生産性乳酸菌を接種して製麹したものであることを特徴とするものである。
【０００９】
請求項３に記載の発明の乳酸発酵食品は、請求項１又は請求項２に記載の乳酸発酵食品の製造方法において、前記低温性乳酸菌としてラクトバチルス・サケ（Ｌａｃｔｏｂａｃｉｌｌｕｓｓａｋｅ）を用いることを特徴とするものである。
【００１０】
【発明の実施の形態】
以下、この発明を具体化した実施形態を詳細に説明する。
実施形態の乳酸発酵食品は、食品素材に米麹を添加するとともに低温性乳酸菌を接種した後、０〜１０℃の低温で所定期間発酵熟成を行うことにより製造される。この乳酸発酵食品は、米麹を用いて発酵熟成させる食品であり、例えば、かぶらずし、大根ずし、いずし、ねずし等が挙げられる。これらの乳酸発酵食品の原料となる食品素材としては、魚肉、畜肉、野菜及び米飯から選ばれる少なくとも１種が用いられる。
【００１１】
前記米麹は、ナイシン（ｎｉｓｉｎ）生産性乳酸菌の培養物を添加することにより該乳酸菌が接種された蒸し米を製麹した第１の米麹、又は栄養成分を含む水に浸漬させた米を蒸煮した蒸し米にナイシン生産性乳酸菌を接種して製麹した第２の米麹が用いられる。第１の米麹は、蒸煮後に冷ました蒸し米に、ナイシン生産性乳酸菌を予め所定の培地中で培養した培養物を添加することにより該乳酸菌を接種するとともに、同蒸し米に麹菌（種麹）を接種することにより製麹したものである。第２の米麹は、ナイシン生産性乳酸菌にとっての栄養成分を含む水を米の浸漬液として浸漬させた米を蒸煮した蒸し米に、ナイシン生産性乳酸菌及び麹菌（種麹）を接種することにより製麹したものである。この第２の米麹は、例えば特開２００１−２２４３５９号公報に開示された製造方法に従って製造される。なお、これら第１及び第２の米麹に接種されるナイシン生産性乳酸菌の接種量としては、接種直後の蒸し米中に含まれる該乳酸菌が検出可能な量（１．０×１０^２個／ｇ以上）であるのが好ましい。
【００１２】
これら第１及び第２の米麹は、前記蒸し米に麹菌を接種した後、好気的な条件下で１５〜３５℃、好ましくは３０℃付近の比較的高温で発酵させることにより、該蒸し米に麹菌を増殖させたものである。さらに、これら米麹は、接種したナイシン生産性乳酸菌が生存することにより発生するアンタゴニズム（拮抗作用）及び該乳酸菌が生産するナイシンの作用により、製麹時に繁殖しやすいバチルス属細菌等の有害細菌による汚染を効果的に阻止したバイオプリザベーション（ｂｉｏｐｒｅｓｅｒｖａｔｉｏｎ）が施されたものである。また、これら米麹の使用に関しては、そのまま食品素材に添加する以外にも、水や食塩等の調味料と混合したものを調製してから用いることもできる。
【００１３】
前記ナイシン生産性乳酸菌としては、例えばラクトコッカス・ラクティス（Ｌａｃｔｏｃｏｃｃｕｓｌａｃｔｉｓ）ＩＦＯ１２００７や同ＡＴＣＣ１１４５４等が挙げられる。これらナイシン生産性乳酸菌は、１５〜３７℃での増殖能及びナイシン生産能が高い中温性の乳酸球菌であり、それら増殖能及びナイシン生産能は１０℃以下の低温では著しく低く、５℃以下ではほとんどない。このナイシン生産性乳酸菌を増殖させるための栄養成分としては、単糖やオリゴ糖、各種ビタミンやミネラル等の微生物（特にナイシン生産性乳酸菌）の増殖に適したものが用いられる。この栄養成分を含む素材としては、米糠、酒粕、大豆、トウモロコシ、麹、味噌、ペプトン、酵母抽出物等が挙げられ、該素材（１種類のみであっても、複数種類混合して用いてもよい）に水を加えたもの、好ましくは水を加えた後に加熱したものが上記所定の培地又は米の浸漬液として用いられる。
【００１４】
なお、上記培養物は、前記培地中にナイシン生産性乳酸菌を接種して該乳酸菌が検出可能（１．０×１０^２個／ｇ以上）となるまで培養したものである。また、この培養物としては、前記蒸煮後に冷ました蒸し米に添加したときに、該蒸し米中に含まれるナイシン生産性乳酸菌が検出可能（１．０×１０^２個／ｇ以上）となる菌体数まで培養したものであるのが最も好ましい。
【００１５】
前記ナイシンは、バチルス属細菌や乳酸菌等のグラム陽性細菌全般に対して強い殺菌作用を持つバクテリオシンの１種である。なお、このナイシンは、大腸菌等のグラム陰性細菌に対して同様の作用を持たない。
【００１６】
前記低温性乳酸菌は、０〜１０℃の低温で優れた増殖能を持ち、さらにその増殖とともに乳酸や酢酸等の有機酸を多量に生産するホモ発酵型の乳酸菌であることが好ましい。この低温性乳酸菌としては、ラクトバチルス・サケやラクトバチルス・カルバタス（Ｌａｃｔｏｂａｃｉｌｌｕｓｃｕｒｖａｔｕｓ）等が挙げられるが、製品（乳酸発酵食品）の呈味性が高いことから、ラクトバチルス・サケが最も好適に用いられる。これら低温性乳酸菌は、グラム陽性の乳酸桿菌である。この低温性乳酸菌の接種量としては、製品化までの発酵熟成期間を短縮するために、該乳酸菌及び米麹が添加された部位（発酵部）中に１．０×１０^２個／ｇ以上存在する量、即ち接種直後の時点で食品検査により検出可能な量である。
【００１７】
前記発酵熟成は、食品素材に米麹の添加と低温性乳酸菌の接種とを行った後の工程であり、好ましくは嫌気的な条件下で行われる。この発酵熟成は、前記食品素材及び米麹に含まれる各種栄養分、及び前記米麹に含まれる各種酵素の作用により生産される栄養分を前記低温性乳酸菌の増殖に利用させる工程である。そのため、この発酵熟成は、前記米麹に付着したナイシン生産性乳酸菌の増殖を抑制するため、０〜１０℃、好ましくは４〜６℃の低温で行われる。これにより前記低温性乳酸菌は、ナイシン生産性乳酸菌に増殖を阻害されることなく速やかに増殖して乳酸や酢酸等の有機酸を多量に生産し、低温でも増殖する大腸菌群等のグラム陰性細菌を速やかに死滅させる。これにより、前記低温性乳酸菌は独占的な細菌叢を速やかに形成して有害細菌による汚染を阻止し、また良好な酸味を醸成して製品の呈味性を整え、製品化までの発酵熟成期間を短縮する。なお、製品の塩分濃度は、前記低温性乳酸菌の活動に悪影響を与えないようにするために７．５重量％以下にする必要がある。
【００１８】
次に、上記乳酸発酵食品の製造方法及び作用について説明する。
この乳酸発酵食品は、図１（ａ）に示される第１の製造方法、又は図１（ｂ）に示される第２の製造方法のいずれかに従って製造される。第１の製造方法は、食品素材に対する米麹の添加と低温性乳酸菌の接種とを同時に行い、その直後から０〜１０℃の低温で発酵熟成させるものである。第２の製造方法は、食品素材に対し、まず低温性乳酸菌を接種して０〜１０℃の低温で所定期間下漬けを行った後、米麹を添加してさらに０〜１０℃の低温で発酵熟成（本漬け）を行うものである。
【００１９】
これら第１及び第２の製造方法では、前記米麹を添加する前に製麹が完了するように米麹を調製する。この製麹を行う際には、まず、前記栄養成分を含む培地でナイシン生産性乳酸菌を培養し、その培養物を添加した蒸し米（ナイシン生産性乳酸菌が接種されている）、又は前記栄養成分を含む浸漬液に米を浸漬し、該栄養成分を含浸させた米を蒸煮した後にナイシン生産性乳酸菌を接種した蒸し米を調製する。次に、この蒸し米に、麹菌を接種して十分に混合した後、好気的条件下で１５〜３５℃の温度で所定期間培養する。
【００２０】
このとき、前記ナイシン生産性乳酸菌は、前記培養（製麹）において終始生存し、上記アンタゴニズム（拮抗作用）とナイシンの殺菌作用とにより、主に製麹環境に由来するグラム陽性細菌（バチルス属細菌）の増殖を抑えつつ死滅させる。また、前記麹菌は、前記培養の全期間を通して、前記蒸し米中に含まれる多糖類や各種栄養分を利用しながら増殖するとともに、前記発酵熟成に必要なアミラーゼやプロテアーゼ等の各種酵素を生産し、それらを米麹中に蓄積させる。
【００２１】
さて、図１（ａ）に示すように、第１の製造方法では、適当なサイズにカットした食品素材に前記米麹を添加するとともに低温性乳酸菌を接種した後、好ましくは嫌気的条件下において、０〜１０℃の低温に保持したまま所定期間発酵熟成させる。このとき、前記低温性乳酸菌は、前記米麹に付着したナイシン生産性乳酸菌よりもその代謝及び増殖に有利な温度環境に置かれていることから、米麹及び食品素材中の各種栄養分並びに米麹中の酵素作用により生産される栄養分を利用して急速に増殖するとともに多量の有機酸を生産してｐＨを急激に低下させる。これにより、食品素材等に由来し低温でも増殖する大腸菌群等のグラム陰性細菌は速やかに死滅し、また前記米麹に含有されていた多量のナイシン生産性乳酸菌も死滅する。その結果、この発酵熟成開始後、前記低温性乳酸菌による独占的な細菌叢が速やかに形成され、有害細菌による汚染が阻止されるとともに乳酸発酵による酸味が付与され、また前記米麹に含まれる各種酵素作用により糖質等による甘味とアミノ酸等による旨味が引き出される。
【００２２】
図１（ｂ）に示すように、第２の製造方法では、まず、適当なサイズにカットした食品素材に予め低温性乳酸菌を接種して、嫌気的条件下で０〜１０℃の低温に保持したまま所定期間下漬けを行うことにより、前記低温性乳酸菌を増殖させ、活動を活性化させる。なお、この下漬けは、通常、食品素材（特に野菜）に食塩を添加して味付けするとともに、食品素材に余剰に含まれる水分を減少させるために行われる。次に、前記米麹を添加してそのままの温度条件下、好ましくは嫌気的条件下で発酵熟成させることにより、上記第１の製造方法と同様に乳酸発酵食品が製造される。なお、この第２の製造方法において、低温性乳酸菌を接種する際の食品素材の塩分濃度は、該乳酸菌の活動に悪影響を与えないようにするために、７．５重量％以下にする必要がある。
【００２３】
これら第１及び第２の製造方法により製造された乳酸発酵食品は、前記米麹が添加された部位のｐＨが４．５以下となった時点で食品検査を行う目安となり、米麹に由来するナイシン生産性乳酸菌が前記食品検査で検出されなくなった時点で出荷が可能となる。
【００２４】
上記実施形態によって発揮される効果について、以下に記載する。
・実施形態の乳酸発酵食品の製造方法は、食品素材に米麹の添加と低温性乳酸菌の接種とを同時又は異なるタイミングで行った後、０〜１０℃で発酵熟成を行うものである。なお、前記米麹は、ナイシン生産性乳酸菌によるバイオプリザベーションが施されたものであり、ナイシン生産性乳酸菌以外のグラム陽性細菌全般による汚染を効果的に阻止したものである。
【００２５】
このため、この乳酸発酵食品の製造方法では、主に米麹から移行し、且つ最終製品において死滅させることが困難であるバチルス属細菌による汚染を効果的に阻止した乳酸発酵食品を提供することができる。また、前記発酵熟成は、低温性乳酸菌を接種して０〜１０℃の低温で行うように構成されていることから、前記米麹から移行したナイシン生産性乳酸菌の増殖は抑制され、接種した低温性乳酸菌による乳酸発酵が速やかに行われる。これにより、この製造方法では、食品素材等に由来し、低温でも増殖する大腸菌群等のグラム陰性細菌を速やかに死滅させることができる。また、自然発酵に頼って行われていた前記従来の製法と比較して、低温性乳酸菌による乳酸発酵が極めて迅速且つ確実に進行するため、短期間で安定した品質の製品を製造することができる。加えて、米麹に加熱等の殺菌処理を施す必要がないため、米麹の色や風味、熟成に関与する各種酵素の活性を損ねることがなく、酵素製剤や人工調味料等を使用せずとも高品質な製品を得ることができる。
【００２６】
・実施形態の乳酸発酵食品の第２の製造方法は、食品素材に低温性乳酸菌を接種して０〜１０℃で下漬けを行った後、米麹を添加してさらに０〜１０℃で発酵熟成（本漬け）を行うものである。このため、この乳酸発酵食品の製造方法は、下漬け工程で予め低温性乳酸菌を増殖させ、活性化させるように構成されていることから、第１の製造方法と比較して、発酵熟成中の乳酸発酵がより迅速に進行する。従って、この第２の製造方法によれば、グラム陰性細菌等の腐敗細菌及びナイシン生産性乳酸菌をより速やかに死滅させ、短期間の発酵熟成で高い品質の製品を製造することが容易となる。
【００２７】
・実施形態の乳酸発酵食品の製造方法は、低温性乳酸菌としてラクトバチルス・サケを用いることにより、０〜１０℃の低温で速やかに乳酸発酵させることができることから、低温でも増殖する大腸菌群等のグラム陰性細菌に対しても強い増殖阻止効果が得られる。さらにこのとき、味や風味といった呈味性に関しても良好なものとなる。
【００２８】
【実施例】
以下、前記実施形態を具体化した実施例及び比較例について説明する。
（試験例１）
有害細菌による汚染がなく良好な酸味の醸成された乳酸発酵食品を製造するため、乳酸発酵させた蒸し米のバチルス属細菌に対する生育阻止効果を調べた。即ち、大豆抽出液を添加した米を蒸して製造した蒸し米にナイシン生産性乳酸菌であるラクトコッカス・ラクティスＩＦＯ１２００７又は低温性乳酸菌であるラクトバチルス・サケＭＭＦ−１６１（サンエイラクトＭＭＦ−１６１）を１０^６ＣＦＵ／ｇになるように接種し、３０℃で２４時間乳酸発酵させた。その後、バチルス・サブチルス（Ｂａｃｉｌｌｕｓｓｕｂｔｉｌｌｉｓ）ＡＴＣＣ１９６５９を１０^５ＣＦＵ／ｇになるように接種した。乳酸発酵前及びバチルス属細菌接種直後（表中では発酵前及び発酵後と記載）における乳酸菌数、バチルス属細菌数及び発酵部のｐＨを調べた。結果を表１に示す。
【００２９】
【表１】

表１に示すように、１０^６ＣＦＵ／ｇになるように接種したナイシン生産性乳酸菌及び低温性乳酸菌は、３０℃で２４時間乳酸発酵させることによりいずれも１０^８ＣＦＵ／ｇにまで増殖した。１０^５ＣＦＵ／ｇになるように接種したバチルス属細菌は、ナイシン生産性乳酸菌の生産したナイシンにより接種直後から速やかに１０^２ＣＦＵ／ｇにまで減少した。これに対し、低温性乳酸菌では、バチルス属細菌に対する生育阻止効果はほとんど見られなかった。
【００３０】
（試験例２）
上記試験例１のラクトコッカス・ラクティスで乳酸発酵させバチルス・サブチルスを接種した蒸し米に種麹（菱六ＳＲ−１０８）を０．１％添加し、３０℃で４２時間製麹して米麹を得た。製麹前後の米麹中の乳酸菌数、バチルス属細菌数及び発酵部のｐＨを表２に示す。
【００３１】
【表２】

表２に示すように、製麹前に１０^２ＣＦＵ／ｇ生残していたバチルス属細菌は、製麹後には検出されなくなり、ナイシン生産性乳酸菌により完全に生育が阻止されたことが示された。一方、コントロール（乳酸菌未接種）では、製麹後のバチルス属細菌数は１０^６ＣＦＵ／ｇにまで増殖した。
【００３２】
（試験例３）
上記試験例２のラクトコッカス・ラクティスを用いて製麹した米麹を使用して、麹漬けの素（飯米：水：米麹：食塩＝５９：３０：１０：１）を調製し、これに大腸菌（Ｅｓｃｈｅｒｉｃｈｉａｃｏｌｉ）ＡＴＣＣ１４９４８を１０^５ＣＦＵ／ｇになるように接種した。続いて、ラクトバチルス・サケＭＭＦ−１６１又は中温性乳酸菌であるラクトバチルス・カゼイ（Ｌａｃｔｏｂａｃｉｌｌｕｓｃａｓｅｉ）Ｌ−１４を１０^５ＣＦＵ／ｇになるように接種した後、１０℃で７日間発酵熟成させた。発酵熟成０日目及び７日目における総乳酸菌数（米麹に由来するラクトコッカス・ラクティス及び本試験で接種したラクトバチルス・サケ又はカゼイを合計した菌体数を表す）、乳酸桿菌数（ラクトバチルス・サケ又はカゼイの菌体数を表す）、大腸菌数及び発酵部のｐＨを調べた結果を表３に示す。
【００３３】
【表３】

表３に示すように、発酵熟成０日目のコントロール（乳酸菌未接種）の麹漬けの素には、米麹に由来するナイシン生産性乳酸菌が総乳酸菌数として１０^６ＣＦＵ／ｇ検出され、また中温性乳酸菌を接種したものでは、その中温性乳酸菌が乳酸桿菌数として１０^５ＣＦＵ／ｇ検出された。これらの乳酸菌はいずれも１０℃での増殖力が極めて弱く、７日間発酵熟成させても大腸菌の生育を阻止することができなかった。これに対し、低温性乳酸菌を接種したものでは、その低温性乳酸菌が乳酸桿菌数として１０^５ＣＦＵ／ｇ検出され、１０℃で７日間発酵熟成させることにより１０^８ＣＦＵ／ｇにまで増殖してｐＨを３．９１にまで低下させ、大腸菌を検出不能になるまで死滅させた。従って、製麹工程でナイシン生産性乳酸菌を用い、発酵熟成工程で低温性乳酸菌を用いて低温にて発酵熟成させることにより、バチルス属細菌及び大腸菌群等の有害細菌による汚染を阻止し、乳酸発酵による良好な酸味が醸成された食品が短期間で製造され得ることが示された。またこのとき、発酵熟成０日目にナイシン生産性乳酸菌が低温性乳酸菌より多く生存していたが、７日間目にはナイシン生産性乳酸菌が検出されなくなり、１０℃という低温で発酵熟成を行うことにより、両者の優勢が完全に逆転したことが確認された。
【００３４】
（実施例１及び比較例１）
実施形態の第１の製造方法において、ラクトコッカス・ラクティスＩＦＯ１２００７を利用して製麹した米麹４５０ｇ及び食品素材を混合した直後に、ラクトバチルス・サケＭＭＦ−１６１を１０^５ＣＦＵ／ｇになるように接種し、５℃で発酵熟成させて「いずし」を製造したものを実施例１とした。なお、前記食品素材は、冷水中で一晩脱塩した塩蔵ベニサケの切り身１ｋｇ、３％の食塩で下漬けした後に水切りしたダイコン及びニンジンの千切り１ｋｇ、並びに飯米１．５ｋｇを混合したものである。また、ラクトバチルス・サケＭＭＦ−１６１を接種しないものをコントロールとしての比較例１とした。発酵熟成０，３，７，１４，２１，２８日後のいずしの一部をサンプリングし、表４に示される各項目について調査した。結果を表４に示す。
【００３５】
【表４】

表４に示すように、実施例１の発酵熟成０日目において、米麹に由来するナイシン生産性乳酸菌と接種した低温性乳酸菌とが総乳酸菌数として１０^６ＣＦＵ／ｇ検出され、低温性乳酸菌が乳酸桿菌数として１０^５ＣＦＵ／ｇ検出された。しかしながら、発酵熟成７日目には、乳酸桿菌数が総乳酸菌数とほぼ同数の１０^８ＣＦＵ／ｇにまで達し、ナイシン生産性乳酸菌は検出されなくなったことが確認された。このとき、発酵部のｐＨが４．３６まで低下するとともに、熟成３日目に１０^３〜１０^４ＣＦＵ／ｇ検出された一般細菌、グラム陰性細菌及び大腸菌群は検出されなくなった。また、１４日間発酵熟成させたものを試食したところ、酸味と甘味のバランスが整い、風味も良好であり、その後２８日まで経過しても一般細菌、グラム陰性細菌及び大腸菌群が増殖しないことも確認された。
【００３６】
一方、低温性乳酸菌を接種しなかった比較例１では、発酵熟成２８日目でも乳酸桿菌は検出されなかった。このとき、米麹に由来するナイシン生産性乳酸菌が総乳酸菌数として１０^６ＣＦＵ／ｇ検出されたが、それらは増殖することができず、グラム陰性細菌及び大腸菌群の増殖を阻止することもできなかったことも確認された。また、２８日経過してもｐＨは５．７０までしか低下せず、良好に乳酸発酵した製品は得られなかった。
【００３７】
（実施例２，３及び比較例２，３）
実施形態の第２の製造方法により「麹漬け大根」を製造した。即ち、大根２．５ｋｇに対し７５ｇの食塩を加えるとともに、低温性乳酸菌であるラクトバチルス・サケ（本発明者らが分離・同定したＬｂ．ｓａｋｅＬＧ−１株）を１０^５ＣＦＵ／ｇになるように接種し、５℃又は１０℃で３日間下漬けした。次に、ラクトコッカス・ラクティスＩＦＯ１２００７を利用して製麹した米麹を使用した漬け床（米飯１５０ｇ、米麹１００ｇ、上白糖１００ｇ、食塩１０ｇ）を添加して、５℃又は１０℃で６日間発酵熟成（本漬け）させた。なお、前記下漬け及び発酵熟成において、５℃で漬けたものを実施例２、１０℃で漬けたものを実施例３とした。また、ラクトバチルス・サケＬＧ−１を接種しないものをコントロールとしての比較例２（５℃）及び比較例３（１０℃）とした。下漬け０日目，３日目，発酵熟成６日目の大根部をサンプリングし、表５に示される各項目について調査した。結果を表５に示す。
【００３８】
【表５】

表５に示すように、低温性乳酸菌を１０^５ＣＦＵ／ｇになるように接種した実施例２，３からは、下漬け０日目で１０^４ＣＦＵ／ｇの乳酸菌が検出され、下漬け３日目には、５℃で１０^６ＣＦＵ／ｇ、１０℃で１０^７ＣＦＵ／ｇにまで増殖した。これに対し、低温性乳酸菌を接種しなかった比較例２，３では、下漬けの前後とも乳酸菌は検出されなかった。さらに、低温性乳酸菌を接種した実施例２，３では、発酵熟成６日目に総乳酸菌数、乳酸桿菌数共に１０^７ＣＦＵ／ｇにまで達し、ナイシン生産性乳酸菌は検出されなくなったことも確認された。このとき、発酵部のｐＨが４．３以下にまで低下し、一般細菌、グラム陰性細菌及び大腸菌群はいずれも検出されなくなった。これに対し、前記比較例２，３では、発酵熟成６日目に米麹に由来するナイシン生産性乳酸菌が総乳酸菌数として１０^５ＣＦＵ／ｇ検出されたが、乳酸桿菌は検出されず、一般細菌、グラム陰性細菌及び大腸菌群の生育を阻止できなかった。また、大根部のｐＨも５．７程度までしか低下しなかった。
【００３９】
（実施例４）
ラクトコッカス・ラクティスＩＦＯ１２００７を利用して製麹した米麹１００ｇに飯米５９０ｇ、水３００ｇ及び食塩１０ｇを混合するとともに、ラクトバチルス・サケＬＧ−１を１０^５ＣＦＵ／ｇになるように接種し、１０℃で３日間発酵熟成させて「麹漬けの素」を調製した。この「麹漬けの素」４００ｇを食品素材約１．２ｋｇに添加し、５℃で発酵熟成させて「かぶらずし」を製造した。なお、前記食品素材は、蕪重量の５％相当量の食塩で蕪を１０℃で３日間漬け込んだ後に水切りしたものに、魚肉重量の６％相当量の食塩で５℃で６日間塩漬け後に水洗したブリ肉の切り身を挟み込んだものである。１０℃で３日間発酵熟成させた「麹漬けの素」及び１０℃で３日間漬け込んだ蕪、及び発酵熟成０，７，１４日後のかぶらずしをサンプリングし、表６に示される各項目について調査した。結果を表６に示す。
【００４０】
【表６】

表６に示すように、漬け込み３日後の蕪及び発酵熟成０日後のかぶらずしには、一般細菌、グラム陰性細菌及び大腸菌群が１０^２〜１０^４ＣＦＵ／ｇ検出された。しかしながら、「麹漬けの素」を添加して５℃で発酵熟成することにより、７日後には乳酸菌が増殖してｐＨが４．５以下まで低下させ、腐敗細菌（一般細菌、グラム陰性細菌及び大腸菌群）は全く検出されなくなった。即ち、５℃，１週間の発酵熟成で腐敗細菌による汚染がなく、良好な酸味が醸成された製品がほぼ出荷可能な状態となったことが確認された。
【００４１】
さらに、前記実施形態より把握できる技術的思想について以下に記載する。
請求項１に記載の乳酸発酵食品の製造方法に用いられる麹漬けの素であって、前記米麹及び低温性乳酸菌を含有することを特徴とする麹漬けの素。請求項１に記載の乳酸発酵食品の製造方法に用いられる麹漬けの素であって、前記米麹及び低温性乳酸菌を含有するとともに、それらを混合してから０〜１０℃で所定期間発酵熟成させたことを特徴とする麹漬けの素。このように構成した場合、腐敗細菌による汚染を容易かつ効果的に防止することができるとともに、短期間で良好に乳酸発酵した乳酸発酵食品を非常に手軽に製造することができる。
【００４２】
【発明の効果】
以上詳述したように、この発明によれば、次のような効果を奏する。
請求項１から請求項３に記載の発明の乳酸発酵食品の製造方法によれば、腐敗細菌による汚染を容易かつ効果的に防止することができるとともに、短期間で良好に乳酸発酵した乳酸発酵食品を製造することが容易である。
【図面の簡単な説明】
【図１】（ａ）は実施形態の乳酸発酵食品の第１の製造方法の概略を示し、（ｂ）は同じく乳酸発酵食品の第２の製造方法の概略を示す。[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a method for producing lactic acid fermented foods such as Kazushi, Izushi, and Nezu. More specifically, lactic acid fermentation that is easy to produce a product that has been lactic acid fermented well in a short period of time while extremely easily and effectively preventing contamination by harmful bacteria such as Bacillus bacteria and coliforms (Coliform). The present invention relates to a method for producing food.
[0002]
[Prior art]
Conventionally, as a method for producing this type of lactic acid-fermented food, for example, as disclosed in Non-Patent Document 1, salted kabura and yellowtail are soaked in rice koji for several days and produced. Is currently being relied upon.
[0003]
[Non-patent document 1]
Takashi Hisada and two others, "Bacterial Flora of Kabazushi from Kanazawa", Journal of the Japan Society for Food Microbiology, Tokyo Microscope Institute, 1997, 14 (2), 111-114.
[0004]
[Problems to be solved by the invention]
However, in the above-mentioned Non-Patent Document 1, Bacillus bacteria are 10 ³ -10 ⁵ / G, 10 coliforms ² -10 ³ Products detected per g are reported. Furthermore, the document also reports that the products of the same manufacturer differ greatly in the number of lactic acid bacteria and the pH, and the quality is not stable. That is, in the production method by natural fermentation described in Non-Patent Document 1, it is considered that these problems occur because the fermentation by lactic acid bacteria is probably not sufficiently stable. These Bacillus bacteria and coliforms contaminate raw materials such as rice koji, vegetables, fish meat, etc., but they impair the taste and texture, so that these raw materials and final products cannot be subjected to heat sterilization. .
[0005]
Bacillus bacterium is a typical spoilage bacterium that contaminates rice koji, but because it forms spores with high heat and chemical resistance, it is difficult to kill them in final products such as Kabushibashi. . Among them, Bacillus cereus is a food poisoning bacterium that grows even at a low temperature of 5 ° C., and thus requires attention. On the other hand, coliforms are regarded as contamination indicator bacteria, and it is necessary to pay attention to foods from which they are detected are not only unfavorable from the viewpoint of food hygiene but also cause food spoilage even under refrigerated conditions. In addition, enterohemorrhagic Escherichia coli O157 can be infected even when a very small amount of several hundred live bacteria enter orally, and in recent years, processed fishery products such as salmon roe have become foodstuffs causing food poisoning. Therefore, caution is necessary.
[0006]
The present invention has been made by paying attention to the problems existing in the prior art as described above. The object of the present invention is to provide a method for producing a lactic acid-fermented food which can easily and effectively prevent contamination by harmful bacteria and can easily produce a lactic acid-fermented food which has been successfully fermented in a short period of time. Is to do.
[0007]
[Means for Solving the Problems]
In order to achieve the above object, the method for producing a lactic acid-fermented food of the invention according to claim 1 is a method for producing a lactic acid-fermented food in which rice koji is added to a food material and fermented and ripened. The rice koji was inoculated with a lactic acid bacterium by adding a culture of a nisin-producing lactic acid bacterium. It is characterized by being made by koji making steamed rice or by inoculating nisin-producing lactic acid bacteria into steamed rice obtained by steaming rice soaked in water containing nutrients.
[0008]
The method for producing a lactic acid-fermented food of the invention according to claim 2 is a method for producing a lactic acid-fermented food, in which rice koji is added to a food material and fermentation aging is performed, wherein the food material is inoculated with a low-temperature lactic acid bacterium to produce a lactic acid-fermented food. After being pickled at 10 ° C., the rice koji is added and fermentation and maturation are performed at 0 to 10 ° C. The rice koji is prepared by adding a culture of a nisin-producing lactic acid bacterium. Is characterized by being inoculated with nisin-producing lactic acid bacteria on koji-produced rice, or steamed rice immersed in water containing nutrients. is there.
[0009]
The lactic acid-fermented food of the invention according to claim 3 is the method for producing a lactic acid-fermented food according to claim 1 or 2, wherein Lactobacillus sake is used as the low-temperature lactic acid bacterium. Is what you do.
[0010]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments embodying the present invention will be described in detail.
The lactic acid-fermented food of the embodiment is produced by adding rice koji to a food material and inoculating a low-temperature lactic acid bacterium, and then fermenting and aging at a low temperature of 0 to 10 ° C for a predetermined period. This fermented lactic acid food is a food that is fermented and aged using rice koji, and examples thereof include kabushizushi, radish, izushi, and nezuzushi. As a food material serving as a raw material of these lactic acid-fermented foods, at least one selected from fish meat, animal meat, vegetables, and cooked rice is used.
[0011]
The rice koji is prepared by adding a culture of nisin-producing lactic acid bacteria to a first rice koji made from steamed rice inoculated with the lactic acid bacteria, or a rice immersed in water containing nutritional components. A second rice koji made by inoculating a steamed rice with a nisin-producing lactic acid bacterium is used. The first rice koji is inoculated with lactic acid bacteria by adding a culture obtained by culturing nisin-producing lactic acid bacteria in a predetermined medium to steamed rice cooled after steaming. ) Is inoculated. The second rice koji is obtained by inoculating a nisin-producing lactic acid bacterium and a koji mold (seed koji) into steamed rice in which water containing nutrients for nisin-producing lactic acid bacteria is immersed as a rice immersion liquid. It is made from koji. This second rice koji is produced, for example, according to the production method disclosed in JP-A-2001-224359. The inoculation amount of the nisin-producing lactic acid bacteria to be inoculated into the first and second rice koji is the detectable amount (1.0 × 10 5) of the lactic acid bacteria contained in steamed rice immediately after inoculation. ² / G or more).
[0012]
These first and second rice koji are prepared by inoculating the steamed rice with koji mold and then fermenting the mixture under aerobic conditions at a relatively high temperature of 15 to 35 ° C, preferably around 30 ° C. It is made by growing koji mold on rice. Furthermore, these rice koji are harmful bacteria such as Bacillus bacterium which are easily proliferated during koji making due to the antagonism (antagonism) generated by the survival of the inoculated nisin-producing lactic acid bacteria and the action of nisin produced by the lactic acid bacteria. The biopreservation which effectively prevented contamination by water was performed. Regarding the use of these rice koji, besides adding them directly to food materials, they can also be used after preparing a mixture with a seasoning such as water or salt.
[0013]
Examples of the nisin-producing lactic acid bacteria include Lactococcus lactis IFO12007 and ATCC11454. These nisin-producing lactic acid bacteria are mesophilic lactococci having a high growth ability at 15-37 ° C and a high nisin-producing ability, and their growth ability and nisin-producing ability are remarkably low at a low temperature of 10 ° C or less and at 5 ° C or less. rare. As nutrients for growing the nisin-producing lactic acid bacteria, those suitable for the growth of microorganisms (especially nisin-producing lactic acid bacteria) such as monosaccharides, oligosaccharides, various vitamins and minerals are used. Examples of the material containing the nutritional component include rice bran, sake lees, soybean, corn, koji, miso, peptone, yeast extract, and the like. Good) and water, preferably heated after adding water, is used as the above-mentioned predetermined medium or rice immersion liquid.
[0014]
In addition, the culture can be detected by inoculating a nisin-producing lactic acid bacterium into the medium (1.0 × 10 4). ² (G / g or more). In addition, as this culture, nisin-producing lactic acid bacteria contained in the steamed rice can be detected when added to the steamed rice cooled after the steaming (1.0 × 10 4). ² Most preferably, the culture is performed up to the number of cells.
[0015]
Nisin is a kind of bacteriocin that has a strong bactericidal action against all Gram-positive bacteria such as Bacillus bacteria and lactic acid bacteria. This nisin does not have the same effect on Gram-negative bacteria such as Escherichia coli.
[0016]
The low-temperature lactic acid bacterium is preferably a homofermentative lactic acid bacterium that has excellent growth ability at a low temperature of 0 to 10 ° C. and further produces a large amount of organic acids such as lactic acid and acetic acid with the growth. Examples of the low-temperature lactic acid bacteria include Lactobacillus salmon and Lactobacillus carvatas. Lactobacillus salmon is most preferably used because the product (lactic acid fermented food) has a high taste. Can be These cold lactic acid bacteria are gram-positive lactic acid bacilli. The inoculum amount of the low-temperature lactic acid bacterium was 1.0 × 10 3 in the site (fermentation part) where the lactic acid bacterium and rice koji were added in order to shorten the fermentation aging period until commercialization. ² It is an amount present in an amount of at least individual / g, that is, an amount detectable by a food test immediately after inoculation.
[0017]
The fermentation aging is a step after adding rice koji to a food material and inoculating a low-temperature lactic acid bacterium, and is preferably performed under anaerobic conditions. This fermentation aging is a step in which various nutrients contained in the food material and the rice koji and nutrients produced by the action of various enzymes contained in the rice koji are used for the growth of the low-temperature lactic acid bacteria. Therefore, this fermentation aging is performed at a low temperature of 0 to 10C, preferably 4 to 6C in order to suppress the growth of nisin-producing lactic acid bacteria attached to the rice koji. Thus, the low-temperature lactic acid bacteria rapidly grow without being inhibited by nisin-producing lactic acid bacteria, produce large amounts of organic acids such as lactic acid and acetic acid, and produce gram-negative bacteria such as Escherichia coli that grow even at low temperatures. Kill immediately. Thereby, the low-temperature lactic acid bacterium quickly forms an exclusive bacterial flora to prevent contamination by harmful bacteria, and also develops a good acidity to improve the taste of the product, and the fermentation aging period until commercialization. To shorten. The salt concentration of the product needs to be 7.5% by weight or less so as not to adversely affect the activity of the low-temperature lactic acid bacteria.
[0018]
Next, a method for producing the above-mentioned lactic acid fermented food and its operation will be described.
This fermented lactic acid food is produced according to either the first production method shown in FIG. 1A or the second production method shown in FIG. 1B. In the first production method, rice koji is added to a food material and inoculation of a low-temperature lactic acid bacterium is performed at the same time, and fermentation and aging are performed at a low temperature of 0 to 10 ° C. immediately after that. In the second production method, a food material is first inoculated with a low-temperature lactic acid bacterium, soaked at a low temperature of 0 to 10 ° C for a predetermined period, and then added with rice koji and further reduced at a low temperature of 0 to 10 ° C. Fermentation and aging (honzuke) are performed.
[0019]
In these first and second production methods, rice koji is prepared so that koji making is completed before adding the rice koji. When performing this koji-making, first, nisin-producing lactic acid bacteria are cultured in a medium containing the nutrient component, and steamed rice (to which a nisin-producing lactic acid bacterium is inoculated) added with the culture, or the nutrient component is added. The rice impregnated with the nutrients is immersed in an immersion liquid containing, and then steamed rice is prepared by inoculating a nisin-producing lactic acid bacterium. Next, the steamed rice is inoculated with koji mold and mixed well, and then cultured under aerobic conditions at a temperature of 15 to 35 ° C. for a predetermined period.
[0020]
At this time, the nisin-producing lactic acid bacterium survives throughout the culture (koji making), and by the antagonism (antagonism) and the bactericidal action of nisin, Gram-positive bacteria (Bacillus sp.) Mainly derived from the koji making environment. Bacteria) to suppress the growth and kill. Further, the koji mold grows while utilizing the polysaccharides and various nutrients contained in the steamed rice throughout the culture, and produces various enzymes such as amylase and protease required for the fermentation ripening, They are accumulated in rice koji.
[0021]
Now, as shown in FIG. 1 (a), in the first production method, after adding the rice koji to a food material cut into an appropriate size and inoculating a low-temperature lactic acid bacterium, preferably under anaerobic conditions, , And fermented and ripened for a predetermined period while being kept at a low temperature of 0 to 10 ° C. At this time, since the low-temperature lactic acid bacterium is placed in a temperature environment more favorable for its metabolism and growth than the nisin-producing lactic acid bacterium attached to the rice koji, various nutrients in the rice koji and food materials and the rice koji It rapidly proliferates by utilizing nutrients produced by the action of enzymes therein, and produces a large amount of organic acids to rapidly lower the pH. As a result, Gram-negative bacteria such as Escherichia coli which are derived from food materials and proliferate even at low temperatures are quickly killed, and a large amount of nisin-producing lactic acid bacteria contained in the rice koji are also killed. As a result, after the start of the fermentation ripening, an exclusive bacterial flora is rapidly formed by the low-temperature lactic acid bacterium, thereby preventing contamination by harmful bacteria and imparting acidity by lactic acid fermentation. Enzyme action brings out sweetness due to saccharides and the like and umami due to amino acids and the like.
[0022]
As shown in FIG. 1 (b), in the second production method, first, a low-temperature lactic acid bacterium is inoculated in advance into a food material cut into an appropriate size and kept at a low temperature of 0 to 10 ° C. under anaerobic conditions. By immersing the lactobacillus for a predetermined period of time, the low-temperature lactic acid bacteria are proliferated and their activities are activated. In addition, this under-pickling is usually performed in order to add salt to a food material (especially a vegetable) and season, and to reduce excess water contained in the food material. Next, the rice koji is added and fermented and ripened under the same temperature conditions, preferably under anaerobic conditions, to produce a lactic acid fermented food in the same manner as in the first production method. In the second production method, the salt concentration of the food material at the time of inoculation of the low-temperature lactic acid bacterium must be 7.5% by weight or less in order not to adversely affect the activity of the lactic acid bacterium. is there.
[0023]
The lactic acid-fermented foods produced by the first and second production methods serve as a guide for food inspection when the pH of the site where the rice koji is added becomes 4.5 or less, and are derived from rice koji. When nisin-producing lactic acid bacteria are no longer detected in the food test, shipment becomes possible.
[0024]
The effects exerted by the above embodiment will be described below.
-In the method for producing a lactic acid-fermented food of the embodiment, after adding rice koji to a food material and inoculating a low-temperature lactic acid bacterium simultaneously or at different timings, fermentation aging is performed at 0 to 10 ° C. The rice koji was biopreserved with nisin-producing lactic acid bacteria, and effectively prevented contamination by gram-positive bacteria other than nisin-producing lactic acid bacteria.
[0025]
For this reason, in this method for producing a lactic acid-fermented food, it is possible to provide a lactic acid-fermented food in which contamination from a Bacillus bacterium which is mainly transferred from rice koji and is difficult to kill in a final product is effectively prevented. it can. In addition, since the fermentation aging is configured to be performed at a low temperature of 0 to 10 ° C. by inoculating a low-temperature lactic acid bacterium, the growth of nisin-producing lactic acid bacteria transferred from the rice koji is suppressed, and the inoculated low-temperature lactic acid bacterium is inoculated. Lactic acid fermentation by the lactic acid bacterium is performed quickly. Thus, in this production method, Gram-negative bacteria such as coliform bacteria derived from food materials and proliferating even at low temperatures can be quickly killed. In addition, compared to the conventional production method that has been performed by relying on natural fermentation, lactic acid fermentation by the low-temperature lactic acid bacterium proceeds extremely quickly and reliably, so that a stable quality product can be produced in a short period of time. . In addition, rice koji does not need to be subjected to sterilization treatment such as heating, so that the color and flavor of rice koji do not impair the activity of various enzymes involved in ripening, without using enzyme preparations or artificial seasonings. A high quality product can be obtained.
[0026]
-In the second method for producing a lactic acid-fermented food of the embodiment, a low-temperature lactic acid bacterium is inoculated into a food material, and then is pickled at 0 to 10 ° C, and then rice koji is added and fermented at 0 to 10 ° C. Aging (honzuke) is performed. For this reason, the method for producing the lactic acid-fermented food is configured so that the low-temperature lactic acid bacteria are proliferated and activated in advance in the under-pickling step. Lactic acid fermentation proceeds more quickly. Therefore, according to the second production method, spoilage bacteria such as gram-negative bacteria and nisin-producing lactic acid bacteria are more quickly killed, and it becomes easy to produce a high-quality product by fermentation aging for a short period of time.
[0027]
The method for producing a lactic acid-fermented food of the embodiment uses lactobacillus salmon as a low-temperature lactic acid bacterium, so that lactic acid fermentation can be carried out quickly at a low temperature of 0 to 10 ° C. A strong growth inhibitory effect is obtained even for Gram-negative bacteria. Further, at this time, the taste properties such as taste and flavor are also good.
[0028]
【Example】
Hereinafter, examples and comparative examples that embody the above embodiment will be described.
(Test Example 1)
In order to produce lactic acid-fermented foods with good acidity without contamination by harmful bacteria, the growth inhibiting effect of lactic acid-fermented steamed rice against Bacillus bacteria was examined. That is, lactobacillus lactis IFO12007 which is a nisin-producing lactic acid bacterium or Lactobacillus salmon MMF-161 (sun elacto MMF-161) which is a low-temperature lactic acid bacterium was added to steamed rice produced by steaming rice to which soybean extract was added. ⁶ CFU / g was inoculated and lactic acid fermentation was performed at 30 ° C. for 24 hours. Thereafter, Bacillus subtilis ATCC 19659 was added to 10 ⁵ CFU / g was inoculated. The number of lactic acid bacteria, the number of Bacillus bacteria, and the pH of the fermentation part were examined before lactic acid fermentation and immediately after inoculation of Bacillus bacteria (in the table, before and after fermentation). Table 1 shows the results.
[0029]
[Table 1]

As shown in Table 1, 10 ⁶ Nisin-producing lactic acid bacteria and low-temperature lactic acid bacteria inoculated so as to have a CFU / g were all subjected to lactic acid fermentation at 30 ° C. for 24 hours. ⁸ Proliferated to CFU / g. 10 ⁵ Bacillus spp. Inoculated so as to have a CFU / g can be rapidly cultivated immediately after inoculation by nisin produced by nisin-producing lactic acid bacteria. ² It decreased to CFU / g. On the other hand, the psychrotrophic lactic acid bacteria showed almost no growth inhibitory effect on Bacillus bacteria.
[0030]
(Test Example 2)
0.1% of seed koji (Ryokuroku SR-108) was added to steamed rice inoculated with Bacillus subtilis by lactic acid fermentation with Lactococcus lactis of Test Example 1 above. Got. Table 2 shows the number of lactic acid bacteria, the number of bacteria belonging to the genus Bacillus, and the pH of the fermentation part in the rice koji before and after the koji making.
[0031]
[Table 2]

As shown in Table 2, 10 ² Bacillus spp. That had survived CFU / g was no longer detected after koji making, indicating that growth was completely inhibited by nisin-producing lactic acid bacteria. On the other hand, in the control (not inoculated with lactic acid bacteria), the number of Bacillus bacteria ⁶ Proliferated to CFU / g.
[0032]
(Test Example 3)
Using the rice koji made with the Lactococcus lactis of Test Example 2 above, koji-zuke (rice rice: water: rice koji: salt = 59: 30: 10: 1) was prepared. Escherichia coli ATCC 14948 ⁵ CFU / g was inoculated. Subsequently, Lactobacillus salmon MMF-161 or Lactobacillus casei L-14, a mesophilic lactic acid bacterium, was added to 10 ⁵ After inoculation to give CFU / g, the mixture was fermented and aged at 10 ° C. for 7 days. Total number of lactic acid bacteria on days 0 and 7 of fermentation and aging (representing the total number of Lactococcus lactis derived from rice koji and Lactobacillus salmon or casei inoculated in this test), the number of lactobacilli Table 3 shows the results obtained by examining the number of Bacillus salmon or casei cells), the number of E. coli, and the pH of the fermentation section.
[0033]
[Table 3]

As shown in Table 3, in the control (not inoculated with lactic acid bacteria) of the koji pickles on the 0th day of fermentation and maturation, nisin-producing lactic acid bacteria derived from rice koji were 10% in total lactic acid bacteria. ⁶ CFU / g was detected and inoculated with mesophilic lactic acid bacteria, the mesophilic lactic acid bacteria contained 10% of lactobacilli. ⁵ CFU / g was detected. All of these lactic acid bacteria had extremely low growth ability at 10 ° C., and could not inhibit the growth of Escherichia coli even after fermentation and aging for 7 days. On the other hand, in the case of inoculated with psychrophilic lactic acid bacteria, the psychrophilic lactic acid bacteria had a ⁵ CFU / g was detected and fermented and aged at 10 ° C for 7 days. ⁸ The pH was reduced to 3.91 by growing to CFU / g and E. coli was killed until it was no longer detectable. Therefore, by using a nisin-producing lactic acid bacterium in the koji making process and fermenting and aging at a low temperature using a low-temperature lactic acid bacterium in the fermentation and ripening process, contamination by harmful bacteria such as Bacillus bacteria and coliforms is prevented, and lactic acid fermentation is performed. It has been shown that a food with good acidity can be produced in a short time. In addition, at this time, the nisin-producing lactic acid bacteria survived more than the low-temperature lactic acid bacteria on day 0 of fermentation ripening, but the nisin-producing lactic acid bacteria were not detected on day 7, and the fermentation ripening was performed at a low temperature of 10 ° C. As a result, it was confirmed that the superiority of the two was completely reversed.
[0034]
(Example 1 and Comparative Example 1)
In the first production method of the embodiment, Lactobacillus salmon MMF-161 is mixed with 10 g of Lactobacillus salmon MMF-161 immediately after mixing with 450 g of rice koji produced using Lactococcus lactis IFO12007 and a food material. ⁵ Example 1 was prepared by inoculating CFU / g and fermenting and aging at 5 ° C. to produce “Izushi”. The food material was a mixture of 1 kg of salted sockeye salmon fillet desalted in cold water overnight, 1 kg of radish and carrot shredded under water with 3% salt, and 1.5 kg of cooked rice. . In addition, a control not inoculated with Lactobacillus salmon MMF-161 was designated as Comparative Example 1 as a control. A part of the izushi after 0, 3, 7, 14, 21, and 28 days after fermentation aging was sampled, and the items shown in Table 4 were examined. Table 4 shows the results.
[0035]
[Table 4]

As shown in Table 4, on the 0th day of fermentation and ripening in Example 1, the nisin-producing lactic acid bacteria derived from rice koji and the inoculated low temperature lactic acid bacteria were 10 ⁶ CFU / g was detected and the number of psychrophilic lactic acid bacteria was 10 ⁵ CFU / g was detected. However, on the seventh day of fermentation and maturation, the number of lactobacilli was about 10 ⁸ It reached CFU / g, confirming that nisin-producing lactic acid bacteria were no longer detected. At this time, the pH of the fermentation section was lowered to 4.36, and 10 ³ -10 ⁴ General bacteria, Gram-negative bacteria, and coliforms detected in CFU / g were not detected. In addition, when tasted for 14 days and fermented and aged, the balance between acidity and sweetness was adjusted, the flavor was good, and even after 28 days, general bacteria, gram-negative bacteria and coliforms did not grow. confirmed.
[0036]
On the other hand, in Comparative Example 1 in which the low-temperature lactic acid bacteria were not inoculated, no lactic acid bacilli were detected even on the 28th day of fermentation ripening. At this time, the nisin-producing lactic acid bacteria derived from rice koji are 10 ⁶ Although CFU / g was detected, it was also confirmed that they failed to grow and could not block the growth of Gram-negative bacteria and coliforms. Further, even after 28 days, the pH dropped only to 5.70, and a product successfully fermented with lactic acid was not obtained.
[0037]
(Examples 2, 3 and Comparative Examples 2, 3)
"Koji- pickled radish" was manufactured by the second manufacturing method of the embodiment. That is, while adding 75 g of salt to 2.5 kg of radish, 10 g of Lactobacillus salmon (Lb. sake LG-1 strain isolated and identified by the present inventors), which is a low-temperature lactic acid bacterium, was added. ⁵ CFU / g was inoculated and submerged at 5 ° C. or 10 ° C. for 3 days. Next, a pickled bed (rice rice 150 g, rice koji 100 g, rice koji 100 g, salt 10 g) using rice koji produced using koji made using Lactococcus lactis IFO 12007 was added, and the mixture was added at 5 ° C. or 10 ° C. for 6 days. Fermented and aged (honzuke). In addition, in the above-mentioned under pickling and fermentation ripening, what was immersed at 5 degreeC was Example 2, and what was immersed at 10 degreeC was Example 3. In addition, those without Lactobacillus salmon LG-1 inoculated were Comparative Examples 2 (5 ° C) and Comparative Example 3 (10 ° C) as controls. The radish was sampled on day 0, day 3, and day 6 of fermentation and aging, and the items shown in Table 5 were examined. Table 5 shows the results.
[0038]
[Table 5]

As shown in Table 5, 10 chilled lactic acid bacteria ⁵ From Examples 2 and 3 inoculated to give CFU / g, 10 ⁴ Lactic acid bacteria of CFU / g were detected. ⁶ CFU / g, 10 at 10 ° C ⁷ Proliferated to CFU / g. On the other hand, in Comparative Examples 2 and 3 in which the low-temperature lactic acid bacteria were not inoculated, no lactic acid bacteria were detected before and after immersion. Furthermore, in Examples 2 and 3 inoculated with low-temperature lactic acid bacteria, both the total number of lactic acid bacteria and the number of ⁷ CFU / g was reached, and it was also confirmed that nisin-producing lactic acid bacteria were no longer detected. At this time, the pH of the fermentation section dropped to 4.3 or less, and general bacteria, gram-negative bacteria, and coliforms were no longer detected. On the other hand, in Comparative Examples 2 and 3, nisin-producing lactic acid bacteria derived from rice koji were 10% in total lactic acid bacteria on the sixth day of fermentation and ripening. ⁵ Although CFU / g was detected, lactobacilli were not detected, and growth of general bacteria, gram-negative bacteria, and coliforms could not be inhibited. Also, the pH of the radish decreased only to about 5.7.
[0039]
(Example 4)
Lactobacillus salmon LG-1 was mixed with 590 g of rice, 300 g of water and 10 g of salt in 100 g of rice koji produced using Lactococcus lactis IFO12007. ⁵ CFU / g was inoculated and fermented and aged at 10 ° C. for 3 days to prepare “Kojizuke-no-moto”. 400 g of this “Kojizuke-no-moto” was added to about 1.2 kg of food material, and fermented and aged at 5 ° C. to produce “Kaburuzushi”. The food material was prepared by soaking the turnip with salt equivalent to 5% of the turnip weight at 10 ° C for 3 days and then draining it. This is a sandwich of the cut yellowtail. "Koji-zuke-no-moto" fermented and aged at 10 ° C for 3 days, turnip immersed at 10 ° C for 3 days, and Kabushiri after 0, 7, and 14 days of fermentation and aging were sampled. investigated. Table 6 shows the results.
[0040]
[Table 6]

As shown in Table 6, common bacteria, gram-negative bacteria and Escherichia coli group were 10% in turnip after 3 days of pickling and in Kabushiri after 0 days of fermentation. ² -10 ⁴ CFU / g was detected. However, the fermentation and aging at 5 ° C. with the addition of “Koji-zuke-no-moto” allow lactic acid bacteria to grow after 7 days and reduce the pH to 4.5 or less, and putrefactive bacteria (general bacteria, gram-negative bacteria and Coli group) was not detected at all. That is, it was confirmed that the fermentation aging at 5 ° C. for one week did not cause contamination by putrefactive bacteria and the product in which a good acidity was brewed was almost ready to be shipped.
[0041]
Further, technical ideas that can be grasped from the embodiment will be described below.
A koji pickled element used in the method for producing a lactic acid-fermented food according to claim 1, wherein the rice koji and the low-temperature lactic acid bacterium are contained. A koji pickled element used in the method for producing a lactic acid fermented food according to claim 1, which contains the rice koji and the low-temperature lactic acid bacterium, and fermented at 0 to 10 ° C for a predetermined period after mixing them. Koji pickled element characterized by having been made. With this configuration, contamination with putrefactive bacteria can be easily and effectively prevented, and lactic acid-fermented foods that have been lactic acid-fermented in a short period of time can be produced very easily.
[0042]
【The invention's effect】
As described above, according to the present invention, the following effects can be obtained.
According to the method for producing a lactic acid-fermented food of the invention according to claims 1 to 3, the contamination with putrefactive bacteria can be easily and effectively prevented, and the lactic acid-fermented food has been successfully fermented in a short period of time. Is easy to manufacture.
[Brief description of the drawings]
FIG. 1 (a) shows an outline of a first method for producing a lactic acid-fermented food of the embodiment, and FIG. 1 (b) also shows an outline of a second method for producing a lactic acid-fermented food.

Claims

In the method of producing lactic acid fermented foods by adding rice koji to food materials and fermenting and aging,
It is configured to add rice koji to the food material and inoculate a low-temperature lactic acid bacterium and perform fermentation aging at 0 to 10 ° C,
The rice koji is produced by koji-making steamed rice inoculated with the lactic acid bacterium by adding a culture of nisin-producing lactic acid bacterium, or nisin is produced by steaming rice immersed in water containing nutrients. A method for producing a lactic acid-fermented food, which is produced by inoculating a lactic acid bacterium with koji.

In the method of producing lactic acid fermented foods by adding rice koji to food materials and fermenting and aging,
After inoculating the food material with a low-temperature lactic acid bacterium and performing under-pickling at 0 to 10 ° C., the rice koji is added and fermentation and aging are performed at 0 to 10 ° C.,
The rice koji is produced by koji-making steamed rice inoculated with the lactic acid bacterium by adding a culture of nisin-producing lactic acid bacterium, or nisin is produced by steaming rice immersed in water containing nutrients. A method for producing a lactic acid-fermented food, which is produced by inoculating a lactic acid bacterium with koji.

The method for producing a lactic acid-fermented food according to claim 1 or 2, wherein Lactobacillus salmon is used as the low-temperature lactic acid bacterium.